Radio receiving system



2 Sheets-Sheet 1 Filed April 16, 1930 nnr Dec. 26, 1933. B. J. CHROMY1,940,661

RADIO RECEIVING SYSTEM Filed April 16, 1930 2 Sheets-Sheet 2 a 63; 55 5a 7 F 57 6 55 6 I 12%;; we 4 v 68 56% 50 draw] UUEZZIEIEI [:IZZIUEIEIINVENTOR. 61

Patented Dec. 26, 1933.

1 This invention relates broadly to radio receiving systems. Morespecifically this invention relates to radio receiving systems arrangedto intercept signaling energy for the operation of frequency selectiveindicators.

An object of this invention is to provide an arrangement whereinsignaling energy intercepted by a receiving system is impressed upon oneor more electro-mechanically vibratile elements for the energizationthereof. I

Another object of this invention is to provide an arrangement whereinsignaling energy intercepted by a receiving system is impressed upon aplurality of electro-mechanically vibratile elements, each having adifferent frequency characteristic, for the energization of 1 selectedones thereof when signaling energy of the proper frequencyv isinterceptedby the receiving system.

'Still' another object of this invention is to provide an arrangementwherein signaling energy intercepted by a receiving system is impressedupon one or more piezo-electric crystals which are caused to glow whenthe signaling energy intercepted is of the proper frequency.

Other features and objects of this invention will be readily apparent tothose skilled'in the art to which this invention is, related from thefollowing specification and the appended claims.

0 This invention is related to radio receiving sysrial Numbers 433,912and 443,564, filed March 7, 1930, and April-11,:1930, respectively.-cordance with "this invention signaling energy transmitted from a radiobeacon located at an] aircraft landing field or' similar port isintercepted by the antenna of :the receiving system located on board themoving vessel which is being'directed or guided to the field or port."The signaling energy; after being amplified to a sufficient degree, isimpressed upon electro-mechan-' ically vibratilepelements; such aspiezo-electric crystals. These crystalsfare'positioned in vesselscontaining rarefied inert gas, such as neon,

45 helium; krypton or mixtures of inert gases; In

those arrangements of this invention where two piezo-electric crystalsare employed, specimens of crystals having frequency characteristicssubstantially alike but displaced in the frequency spectrum by about onekilocycleare selected. Crystals having frequency characteristics spacedby more or less than onekilocycle may be conveniently used, if desired;in cases where this system is employed onvthe shorter wave lengths itmay be desirable to use crystals spaced by less tems disclosed in mycopendingapplications Sereadily understood from the drawings, in which:

Fig. 1 illustrates an embodiment of this invention;

' Fig. 2 illustrates a modified form thereof; a

Fig. 3 shows graphically thenianner in which beams of signaling energyareradiated from the radio beacony' Fig. 4 illustrates a top plan viewelectriccrystal mounting;

Fig.5 isfa view in 'side'elevation of the piezoelectric crystalmounting;H Fig. 6 is'a detail view of the electrode employed with the crystal,and a f 0 Fig. I shows a modified form of piezo-electric crystalmounting. 1 Y Y Referring to Fig. l in detail, reference numeral 1designates a directional, antenna of the loop type. Antenna '2 iscoupled tothe 'circuit of antenna 1 thru the transformer 3 for thepurpose of feeding signaling energy'of the proper of the piezo- 75 phaserelationupon the circuit of antenna 1 and "thereby give the wholeantenna array the desired cardioidal field strength characteristic. The

coupling between the windings of the transformer 3 may be varieduntilthe proper energ transfer takes place between thecircuit of antenna 2and the antenna 1. The condenser 5 'is employed to adjust the period ofthe loop antenna. The condenser 4 is connected into the circuit ofantenna 2 for the purpose of providing a frequency adjusting meanstherefor. Inductance 6 is connected between thelcop antenna and thetuned circuit comprising inductance 8 and condenser-7. Inductances ,9and 10 are shunted by variable condensers 11 and 12and are alsovariablycoupled to the inductance 8. One ofthe inductances 9 and 10 maybe eliminated in cases where piezoelectric crystals 24 and 25 which areconnected 1 5 into the output circuit of electron discharge device 18have frequency characteristics 'not'wide ly separated. In cases wherethese crystals have "frequency characteristicsdiffering substantially,that is, by more than 'five kilocycles from-each other, it isadvantageous to employ two secondary coils 9 and 10 separately tuned. Itis, of course, understood that the secondary of the coupling transformer15, which couples thehigh frequency amplifier.16 to the electrondischarge device 13, may also be in two sections separatelytuned. Thetransformer l7' is connected to'couple the amplifier 16 .to the electrondischarge device 18. This latter transformer may be designed 'to besufficiently aperiodic so that the desired highfrequency signals areefficiently transmitted by it to the electron discharge device 18, or

it likewise may be provided with two separately tuned secondarywindings. V r I v The piezo-electric crystals 24 and 25 are mounted inthe envelope'23, which'is' of glass or other similar transparentmaterial. Each of the crystals is positioned in a separate compartment.This, however, is not essential; since they may both be in the samecompartment, although it is desirable; because in operation it'n'iay bedesir-able to fill the compartment of one crystal with an atmosphere ofrarefied neon gas orsomeother inert 'gasor mixture of inert gases, whileit may be desirable to fillthe other compartment with some such gas ashelium or argon at a, lowpres sure. I

The-crystals24 and 25 are connected in parallel across the choke coil 20and thecondenser 19. The dimensions of the coil 20, the condenser 19 andthe-piezo-ele ctric crystal holders arepreferably such as, to cause thecircuits of. these crystals'to be resonant to frequencies corre-'sponding substantially to the frequencies of the crystals. The chokecoil 20 is,'therefore, preferably of large inductance ascompared to itsdistributed capacity. chokexcoil may be made up of several honeycombcons 'aifranged'in source of current supply 21.

device 13.;

spaced relation. V V

By-pass condenser 22 is connected across the Source of current supply 14is connected into the anode circuit of In operation theradio beaconsending out signaling energy for the guiding of moving-craft to the portis arranged to send outat'leasttwo beams, as shown in Fig. 3.

Zone A of one of the beams is of one frequency, for example, 3,000kilocycles, while zone B is a beam of another frequency, forexample,.,3, 005

kilocycles, and zone ,C is a beam of both of these frequencies. 'ZoneCconsists of those portions of the two. beams transmittedfrom the beacon;which overlap. When the aircraft or similar v'esa. sel which is beingguided into the airport is traveling-in zoneA, then signaling energy-of,for

example, 3,000 kilocycles being intercepted and .impressed upon thecircuits of the piezoelectric crystals2 1 and 25, and that, crystalwhich has a fundamental frequencyof 8,000 kilocycles will be energized,whereupon thev rareficd atmosphere of inert gas surrounding it will becaused to glow. Ifthe aircraft is proceeding in the' zoneB in which the3,005 kilocycle signal is .beingtrans- .mitted, then the otherpiezoelectric crystal,

that is, the one having a fundamental'frequency of 3,005. kilocycles,will be energized and the rarefied inert gas atmosphere surrounding'itwill be caused to glow. When, however, the aircraft isin the. zone C inwhich signals of both frequencies'are being transmitted both crystalswill be energized and the gases surrounding both of" them will-glow. Theoperator of the craft will ,thenbe informed ofthe fact ;that the craftisproceeding toward the beaconsecondary windings of transformers 43 'and44 ,zneon'; helium or similar inert gas orniixture' of In. Fig. '2 amodified form of thisinvention in which two antenna arrays consisting ofloops 2'7 and non-directional antenna 26 and loop 33 and non-directionalantenna32, respectively, are coupled to. theiinput circuits of separateamplifier systems.v The antenna 26 having a tuning con denser 30 and acoupling transformer 28 asso-' ciated therewith is coupled by means ofthe transformer 28 to the circuitof loop 2'7. A tuning condenser 29 isprovided as ameans for adjusting the period of the loop 27. The inputcircuit 7 'of the electron discharge device 31 is connected to thecircuit of'the loop 27. The electron dis- "charge'device 37 is connectedacross the tuning condenser 35 which is employedifor adjusting theperiod of the loop 33. Coupling transformer S i-is provided for couplingthe circuits of the antenna 32 and the loop 33. A-tuning condenser 36 isconnected into the circuit of antenna 32. A

source of anode current supply 38 is connected to the electron dischargedevices 31 and 37. Transformers 39 and 40 are connected into the anodecircuits of the: devices 31 and 37, respectively,

for coupling the circuits thereof to the amplifiers 41 and i2,respectively; Transformers 43 and 44 are employed to couple the electrondischarge devices 45 and 46 to the output circuits of. the ame pliiiers{11 and 4 2, respectively. Source of current supply 47 is connected tothe devices 45 and 46i The choke coils 48fand49 are similar to'the chokecoil 20;,of Fig. 1. These coil'sare connected to the anodesofthe devices45 and ifi. Condensers 50 and time connected in series with the piezoelectric crystals 53 and 54, respectively. The crystal-53 is arrangedto'be energized'by energy from the device 45-and the crystal 5 i'iromthedevice 46.- This arrangement for energizingythe crystals may beemployed in the form of this invention illustrated inFig. 1,'- in which:case the would both be coupled to the primary" or transformer '17. Atransparent envelope 52. is provided forth'e crystals 53' and 54 v I 5 V.Theoperation of the arrangement of this invention illustrated inFig. 2is similar to that form illustrated in Fig. 1, exceptth'at the signalingenergies of different frequencies are intercepted bydifferent antennaarrays and are separately amplified. 1 7, 'l

In Fig.4 a top plan view-of one :of the. piezoelectric crystalindicatorsis-illustrated. A piezoelectric crystal 66 is mounted withinthe. transparent:envelope 60 in anatmosphere of rarefied inert gases;

" The crystalec is mounted'upon a'fiat plate as illustrated in Fig.5."Projecting members 67a and 660, illustrated inFigs. 5 and fi,areprovided to the 'p1ate'66a.. These projecting members are positionedon the, edges of the plate; to retain the crystal in position.

- A screen electrode 65 is positioned" upo n ith e exposed face of thecrystal. Thiselectrode 65 about the. stem 70. The supports 68b areattached to this tubular member '70. Springs 6'7 are attached to theprojecting members 67a and, together with the supporting members 61,which are attached to the member 66b, illustrated in Fig. 5, serve tosupport the crystal upon the stem '70. A base 71 is provided to theenvelope 60. This base is arranged to fit into a socket in such a mannerthat prongs 71a contact with contacts of the socket. The plate 66a andthe screen 65 are connected to the prongs 71a. The screen electrode 65may be slightly displaced from the face of the crystal in cases where amore sensitive indicator is desired, and in those cases the members 68are maintained in contact with the crystal in order to hold it in place.Where it is desired even the members 68 may be displaced from thesurfaces of the crystal and small glass beads fastened to these membersmay be provided to engage the crystal surface.

In Fig. '7 'a simplified piezo-electric crystal indicator is shown. Inthis form of indicator the crystal "i7 is mounted in the vessel '12 ofrarefied inert gas between the contact plates '76 which are connected bymeans of the wires '75 to the prongs 73a. The crystal, together with theplates 76, is supported by the wires '75 upon the stem "74. A base 73 isprovided for retaining the indicator device in a suitable socket.

While several embodiments of this invention have been illustrated anddescribed in considerable detail, it is, of course, to be understoodthat I do not desire to limit this 'mvention to those details as setforth except in so far as they may be defined by the appended claims.

What I claim and desire to secure by Letters Patent of the United Statesis as follows:

1. In course finders adapted to be carried by aircraft the combinationof an antenna system, signal receiving and amplifying means, indicatingmeans including a pair of electro-mechanically vibratile elementsconnected to said signal receiving and amplifying means, said elementsbeing resonant to slightly different radio frequencies, and means forexciting said elements at carrier frequencies transmitted from a groundstation.

2. In course finders adapted to be carried by aircraft the combinationof an antenna system, signal receiving and amplifying means connected tobe energized by signaling energy intercepted by said antenna system, apair of electro-mechanically vibratile elements resonant'to slightlydifferent radio frequencies connected to the output circuit of saidamplifying means and means for exciting said elements at carriersignaling frequencies transmitted from a ground station.

3. In course finders for aircraft the combination of a plurality ofelectro-mechanically vibratile elements carried by said aircraft, eachof said elements being adjusted to resonate at a slightly differentfrequency, signal transmitting means for transmitting signaling energyhaving carrier frequencies corresponding to each of the resonantfrequencies of said elements and signal receiving and amplifying meansfor intercepting and amplifying signals from said transmitting means forenergizing said elements in accordance with said signaling energy. s

4. In course finders for aircraft the combination of a directionalantenna system, signal receiving and amplifying means connected to beenergized by signaling energy intercepted by said antenna system and apair of piezo electric crystals connected to the output of saidamplifying means, said piezo electric crystals being ground to resonateat slightly displaced radio frequencies. 1

5. In course finders for aircraft the combination of a directionalantenna system, signal receiving and high frequency amplifying meansconnected to be energized by signaling energy intercepted by saidantenna system, a pair of piezo electric crystals connected to saidamplifying means, said piezo electric crystals being ground to resonateat slightly displaced radio frequencies.

6. In course finders for aircraft the combination of a directionalantenna, electron discharge device amplifying means having input andoutput circuits, means for coupling said antenna to the input circuit ofsaid amplifying means, a pair of vibratory members adapted tobeenergized at radio frequencies, said vibratory members being adjusted toresonate at slightly different radio frequencies, means for impressinghigh frequency signaling energy'upon said vibratory members, connectionsbetween said last mentioned means and the output circuit of saidamplifying means and glow discharge means arranged to be energized whensaid vibratory members'are energized by signaling energy transmittedfrom a ing ground to resonate at slightly different radio frequencies,means for impressing high frequency signaling energy upon said piezoelectric crystals, 7

connections between said last mentioned-means and the output circuit ofsaid amplifying means, and glow discharge means arranged to be energizedwhen said piezo electric crystals are energized by signaling energytransmitted from a ground station,

BEN J. CHROMY.

